private bool TryComplete(Exception error = null) { bool completeTask; lock (SyncObj) { AssertInvariants(); // If we've already marked the channel as completed, bail. if (_doneWriting != null) { return(false); } // Mark that we're done writing. _doneWriting = error ?? ChannelUtilities.DoneWritingSentinel; completeTask = _items.IsEmpty; } // If there are no items in the queue, complete the channel's task, // as no more data can possibly arrive at this point. We do this outside // of the lock in case we'll be running synchronous completions, and we // do it before completing blocked/waiting readers, so that when they // wake up they'll see the task as being completed. if (completeTask) { ChannelUtilities.Complete(_completion, error); } // At this point, _blockedReaders/Writers and _waitingReaders/Writers will not be mutated: // they're only mutated by readers/writers while holding the lock, and only if _doneWriting is null. // We also know that only one thread (this one) will ever get here, as only that thread // will be the one to transition from _doneWriting false to true. As such, we can // freely manipulate _blockedReaders and _waitingReaders without any concurrency concerns. ChannelUtilities.FailInteractors <ReaderInteractor <T>, T>(_blockedReaders, error); ChannelUtilities.FailInteractors <WriterInteractor <T>, VoidResult>(_blockedWriters, error); ChannelUtilities.WakeUpWaiters(ref _waitingReaders, result: false); ChannelUtilities.WakeUpWaiters(ref _waitingWriters, result: false); // Successfully transitioned to completed. return(true); }
private bool TryComplete(Exception error = null) { lock (SyncObj) { AssertInvariants(); // Mark the channel as being done. Since there's no buffered data, we can complete immediately. if (_completion.Task.IsCompleted) { return(false); } ChannelUtilities.Complete(_completion, error); // Fail any blocked readers/writers, as there will be no writers/readers to pair them with. ChannelUtilities.FailInteractors <ReaderInteractor <T>, T>(_blockedReaders, ChannelUtilities.CreateInvalidCompletionException(error)); ChannelUtilities.FailInteractors <WriterInteractor <T>, VoidResult>(_blockedWriters, ChannelUtilities.CreateInvalidCompletionException(error)); // Let any waiting readers and writers know there won't be any more data ChannelUtilities.WakeUpWaiters(ref _waitingReaders, result: false, error: error); ChannelUtilities.WakeUpWaiters(ref _waitingWriters, result: false, error: error); } return(true); }